Confirmatory factor analysis of the Childhood Anxiety Sensitivity Index
The current study examined the internal structure of the Childhood Anxiety Sensitivity Index (CASI; Silverman, Fleisig, Rabian, & Peterson, 1991) in an ethnically diverse sample of anxious children (N = 311) ranging in age from 5 to 18 years. Based on theory and research on the Anxiety Sensitivity Index (ASI; Reiss, Peterson, Gursky, & McNally, 1986), three measurement models were hypothesized, (a) a model with three correlated factors that represent somatic, mental and social concerns of anxiety sensitivity (AS), (b) a single factor model, and (c) a hierarchical model in which a higher-order factor of AS was posited to explain the relationships among the three first-order factors. The model parameters were estimated using the Weighted Least Squares procedure with Polychoric correlations. Multiple indices of fit suggested that each of these models demonstrated adequate fit to the data. The three factor model did not significantly improve the fit over a single factor model. The three factors were highly correlated, suggesting the presence of a strong higher order factor. A substantial portion of the item relations remained unexplained by these three models. Post-hoc model fitting identified a model with superior fit, a model with one general factor of AS and three specific factors of AS. All items loaded significantly on the general factor, and 12 items also loaded significantly on their respective specific factors. The items comprising the social concerns factor possessed substantial variance unexplained by either the general or specific factors. These findings support the use of a single score of CASI in clinical and research use, as well as indicate the potential utility of subscales. Limitations of the study and implications for future research are discussed.